1. Field of the Invention
The present invention relates to a viewing distance sensor for a television receiver, and more particularly to a proximity sensor which controls the transmission of infra-red signals for sensing the approach distance of a viewer according to a sensed state of the viewing distance.
2. Description of the Prior Art
In conventional proximity detection apparatus as shown in FIG. 2, if an infra-red signal is transmitted from the infra-red signal transmitter 31 installed in a television receiver at the front of the television receiver and is thereafter reflected by a viewer positioning at the front of the television receiver and is received at the infra-red signal receiver 32 installed in the television receiver, then the received infra-red signal is amplified by the preamplifier 33 in the infra-red receiver 32 which generates a control signal applied to the screen controller 34; and at this time a screen control signal is outputted at a terminal a by the screen controller 34 to interrupt an image signal on the screen of the television set.
However, such conventional apparatus has drawbacks in that it may influence the remote control operation of other electronic equipments responsive to infra-red control installed in the vicinity of the television receiver because during the operation of the television receiver the infra-red signal transmitter transmits an infra-red signal may cause the faulty operation of other electronic equipments. Moreover, in such conventional apparatus, image signals on the television screen may be inhibited because it believes a viewer is adjacent the television receiver within a viewable distance, when in fact the infra-red signal is transmitted from infra-red signal transmitters in other electronic equipments and received by the infra-red signal receiver installed in the television receiver since the infra-red signal receiver always remains in the operation state during the operation of the television receiver.